Robots of the above-mentioned type are already known from the state of the art. With these robots, it is a drawback that they have to carry quite a large volume of water for cleaning purposes. This is especially problematic when they are moving on surfaces that are arranged orthogonally with respect to the ground such as window panes. This is associated with a high expenditure of energy since a large amount of water has to be transported. It is also a drawback that more energy has to be expended in order to hold the robot against the window panes, especially by means of negative pressure.
In some cases, robots of the state of the art need an external water supply. Here, the water has to be pumped through a hose connection from a reservoir. Once again, this calls for extensive equipment.
Moreover, it is disadvantageous that the robots apply a relatively large amount of water and thus cleansing agents to the smooth surfaces that are to be cleaned in order to perform a thorough cleaning This constitutes a burden on the environment.
Excess water can especially result in streaks or smears on window panes. Finally, it is a drawback that excess water can drip onto the window sills.